Cluster management
operations

To start and stop a cluster, use the start-dfs.sh and
stop-dfs.sh commands respectively. To balance data in a cluster with
federated NameNodes, run the HDFS Balancer. To decommission a DataNode from a federated
cluster, add the DataNode details to an exclude file and distribute the file among all the
NameNodes in the cluster.

Balance data in a federationDepending on your requirements, you can use the HDFS Balancer to balance data either at the level of the DataNodes or the block pools in a cluster with federated NameNodes.

Decommission a DataNode from a federationTo decommission a DataNode from a federation, you must add the node to the exclude file and distribute the updated exclude file among all the NameNodes. Each NameNode decommissions its block pool. When all the NameNodes finish decommissioning a DataNode, the DataNode is considered decommissioned.